Nominal Voltage

A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class (e.g., 120/240 volts, 480Y/277 volts, 600 volts).

Informational Note No.1: The actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment.
Informational Note No.2: See ANSI C84.1-2011, Voltage Ratings for Electric Power Systems and Equipment (60 hz).
Informational Note No.3: Certain battery units may be considered to be rated at a nominal 48 volts DC, but may have a charging float voltage up to 58 volts. In DC applications, 60 volts is used to cover the entire range of float voltages.